This started out to be a video blog about the way short, tight hamstrings impact your posture. But in order to stretch your hamstrings effectively, you’ll need some information about your hips joints. So, first things first. We know that the hip is a ball and socket joint, but we may not realize how much the inclination of the pelvis affects the joint. When you sit with your pelvis rolled back, tail tucked under, the head of the femur (the ball) rolls slightly outward and slips ever so slightly forward in the “socket” of the pelvis. When that happens, your lumbar spine flexes, your ribcage drops, and your head juts forward—a tumbling house of cards. In that position, there’s a tendency to let the belly muscles slacken, because if they were taut, you wouldn’t be able to breathe! At that point, your iliopsoas, a muscle that should be able to freely lengthen and shorten when you walk, acquires the habit of being a short, tight trunk stabilizer.
In contrast, if you sit with your pelvis inclined slightly forward—think of letting your pubic bone rest down so it’s on the same plane as your tailbone—then the femur heads tuck nicely back into their sockets, making for a much more balanced and secure sitting foundation. You achieve a gentle forward curve in your lumbar spine, which supports the uplift of your chest and head. All this does wonders for your capacity to breathe, to digest your lunch, and to see the world around you. The psoas muscle is elongated in this configuration, and not acquiring any compressive habits. (Don’t miss the Sitting Lesson in my Heal Your Posture DVD!)
All this matters a lot for driving, because when you move your driving leg to press the gas and brake, you flex your hip joint, engaging the psoas. If your psoas is short and tight, it can’t flex your hips as efficiently as it can when you sit with your hip joints well positioned in their sockets. That’s why your driving leg and hip get out of sorts on long trips in the car.
The accompanying video was made on a rainy April day, before I bought my lighting equipment. But still, I think you’ll see what I mean about the hips.